User interface for a portion of a display screen



The FIGURE is a front view of a user interface for a portion of a display screen showing our new design.

The broken lines shown in the drawings are included for the purpose of illustrating portions of the user interface that form no part of the claimed design. The broken line showing of the display screen forms no part of the claimed design. 

The ornamental design for a user interface for a portion of a display screen, as shown and described. 